Production of electrical variations



eh 7 c. cs. SMITH PRODUCTION OF ELECTRICAL VARIATIONS Original Filed May5. 1921 Sam vmew vx Patented Feb. 8, 1927.

' -UNITED STATES MENTS, TO RAYTHEON MANUFACTURING COMPANY, SETTS, ACORPORATION OF MASSACHUSETTS.

CAMBRIDGE, IIIIZASSACEU- PRODUCTION OF ELECTRICAL VARIATIONS.

Application filed May 3, 1921, Serial No. 466,518. Renewed January 11,1927.

Smith Serial No. 415,536, filed October .8,- 1920, and Serial No.418,263, filed October As disclosed in the applications above re- Fig. 1represents a section in elevation of a ferred to, the employment ofcurved electrodes immersed in a gas with all available paths forconduction through the gas short i and of the order of magnitude of themean free path of the electrons and with all paths through theinsulating medium sufficiently long to prevent breakdown and with amagnetic field introduced in the space separating the surfaces of theelectrodes at different potentials permits conduction to freely takeplace between the surfaces of the electrodes in one. direction but notin the oppo-r site direction, thus alfording a simple and convenientmeans .for the rectification of alternating currents. The ability ofsuch a device to successfully rectify depends, as

stated, upon the separation of the electrodes and in addition upon thestrength and character of the magnetic field and the pressure of gas inwhich the electrodes are immersed.

It has been discovered-that if the lines of force of the magnetic fieldare curved and concave toward the cathode the electron discharge islocalized and concentrated in a mannerto markedly improve therectifying.

qualities of the? apparatus, more particularly by greatly increasing thepermissible range of magnetic field over which rectification can takeplace.

In one form of the invention a magnetic field is introduced between twoelectrodes with curved lines of force extending lengthwise of theelectrodes and concave toward one of the electrodes in such a mannerthat the lines of force intercept the surface of this electrode at twopoints spaced length- .wise of the electrode. With such a constructionand with an electric field created between the electrodes, conductiontakes a manner that all paths-. available for conconduction tends tobecome concentrated or bunched in the region beneath the center of thearches formed by the curved lines of force; The region in whichconduction is concentrated may be indicated approximately by a radlallane intersecting the arches of the lines of ibrce at approximatelytheir central points. 7'

Referring to the accompanying drawings tube embodlying the principles ofthe invention, and ig. 2 is a diagrammatic view illustrating the .tubeemployed as a rectifier in a simple circuit.

The tube shown in the illustrated embodiment of the invention comprisesa gas'filled receptacle 10 of. suitable form haying cooperatingcylindrical electrodes 12 and 13 received therein. The electrode 12' issupported "concentrically withinv the receptacle by supporting members14' which extend- 5 from the inner surface of the electrode to a baseportion'16 forming a part of the receptacle. The cooperatingv electrode0 linder 13 is supported in alikemanner y members 18 ;which extend toabase portion 20 formed in the opposite end of the receptacle 10. The twoelectrodes; are .designed with respect to one another in such ductionthrough the'gas' are short and all pathsthrough the insulating mediumare sufficiently long to avoidbreakdown. The

inner electrode cylinder 12 is connected with a lead', 22 pas'singoutwardly through the base 16 and the outer electrodecylinder 13 isconnected with a lead'l24 passing outwardly through the base-20 at theopposite end of the rece tacle. Y

A magnetic eld of suitable strength and having its lines of force curvedand concave with respect to the outer electrode is introduced into thespace separatin the two electrodes to cause gaseous con uction to takeplace when the outer electrode is negative and to prevent gaseousconduction when the inner electrode is negative. This magnetic field maybe conveniently supplied by annular pole pieces 26 and 28 which encirclethe receptacle 10, as indicated, the magnetic field being created in thespace between the upper and lower pole pieces. A plurality of permanentma 'nets 30 and 32 operate in conjunction w1th the pole pieces voltagesand conduction cannot take place.

The thee underlying this type of construction is lieved to beessentially as follows: When the outer cylinder, toward which the linesof force are concave, acts as the cathode electrons starting from aregion adjacent. the upper or lower portions of the cylindrical cathodeare deflected by the magorigin.

netic field toward the center, these electrons in general producin apositive ion nearer the center of the arc es than their points of 'Thesepositive ions dropping to the cathode liberate more electrons which inturn are deflected toward the center of the arches,-this process beingrepeated until the discharge .is concentrated in the region adj acentthe radial plane indicated by dot and dash lines. Electrons liberated inthis plane are not deflected either above or below it but tend toliberate ions in the plane of origin. It will thus be obvious that thedischarge tends to build up with the greatest intensity in the regionimmediately adjacent.

to the meridian plane. On the other hand, electrons leaving the innercylinder when the latter acts as a cathode are dispersed and.

dissipated away from the center of the arch by the curvature of themagnetic field to a region of lesser magnetic field so that positiveions liberated by the impact of these electrons in turn liberateelectrons in a region of small magnetic field and there is. no tendencyfor a continued discharge to take place. It should be understood thatthe curvature or distortion of the path of the electrons lengthwise ofthe electrodes by a magnetic field of the character described is inaddition to andapart from the distortion of the path of electrons by themagnetic field in planes extending radially of the electrode members, aspreviously described in certain of my other copending applications. Theintroduction of auniform or non-symmetrical magnetic field between twoelectrodes tends to cause rectification but does not necessarily tend tolocalize or concentrate the conduction in a single plane as is the casewith the present construction.

Fig. 2 illustrates a simple form of circuit embodying the tube as arectifier, this'circuit comprising an input circuit indicatedrectifies'the high volta e alternating current delivered thereto. Thisoutput circuit may be connected with any desiredform of loadcircuit(notshown) to utilize the high voltage current so rectified.

Although the illustrated embodiment ofthe invention is shown in a tubehaving the lines of force of the magnetic field curved with respect tothe electrode surfaces, it should be understood by art that the broaderpr1nciples of the invention are susceptible of embodiment in any tubedesigned to cause the cathode surface to be intersected at a pluralityof points by the lines of force of the magnetic field, as for example atube having a curved cathode surface intersected at a plurality ofpoints by the lines of force.

. The radial surface of electrode 12, which extends outwardly from thediameter of the smaller active portion of electrode 12 to the diameterof the outer tubular electrode 13 intermediate the reentrant stem 16 andthe space between the two electrodes where the electrical dischargeoccurs, together with the peripheral surface which extends lengthwise ofthe tube from the outer edge of said radial surface in closejuxtaposition to the wall of the tube, with a thin gas space be--.

tween the peripheral surface and the tube wall, protects that portion ofthe tube where the conductor 22 enters the tube from the electricaldischarge and the radiation of light and heat therefrom.

I claim:

1. An electrical apparatus, comprising innerand outer electrodesimmersed in a gas, means for creating an electric field between thesurfaces of the electrodes, and means for introducing a magnetic fieldbetweenv the electrodes, having the lines of force between theelectrodes curved and concave toward the surface of the outer electrode.

' 2. An electrical'apparatus, comprising a hermetically sealed as-filledtube, inner and outer electrodes 0 circular cross-section supported inconcentric relation within the tube, means for creating an electricfield between the surfaces of the electrodes, and means for introducinga magnetic field between'the electrodes, having the lines of forcecurved and concave with respect to the surface of the outer electrode.

3. An electrical apparatus, comprising ahermetically sealed gas-filledtube, inner and outer electrodes of circular cross-section positionedwithin the tube, means for creating an electric field'between theelectrodes, and means for introducing a magnetic field between theelectrodes, comprising annular pole pieces surrounding'the outside ofthe receptacle and spaced apart lengthwise of the electrode.

4. An electrical apparatus comprising cothose skilled in the operatingelectrodes immersed in a gas, means for creating an electric fieldbetween the surfaces of the electrodes, and means for introducing acurved magnetic field between the electrodes having the lines of forcecutting one electrode and arranged to concentrate ionization in a regionrestricted longitudinally of the electrodes.

5. An electrical apparatus comprising cooperating electrodes immersed ina gas, means for creating an electric field between the surfaces of theelectrodes, and means for introducing a magnetic field between theelectrodes with the lines of force extending in such a manner and ofsuch a character that ionization is dissipated with one of theelectrodes acting as the cathode.

6: An electrical apparatus comprising electrodes immersed in a gas andhaving opposing surfaces separated by a distance which is short andcomparable to the mean free path of electrons in the gas, means forintroducing a magnetic field between the electrodes, the magnetic fieldand the electrode surfaces being curved relatively to one another. I

7. An electrical apparatus comprising a gas filled ieceptacle, means forimpressing an electric field in a portion of the gaseous region limitedin length to a distance comparable to the mean free path of electrons inthe gas, and means for introducing a magnetic field in the gaseousregion having the lines of force curved.

8. An electrical apparatus comprising electrodes immersed in a gas andseparated by a distance comparable to the mean free path of theelectrons in the gas. and means for introducing a magnetic field betweenthe electrodes with the lines of force cutting one of the electrodesurfaces at a plurality of points.

9. An electric discharge tube having a reentrant stem, a tubularelectrode having one end directed towardsaid stem, an electrode surfacepresented to the interior of said gas space.

the tubular electrode and a surface extend- 1 ing lengthwise of the tubefrom the outer edge of said transverse surface.

10. An electrical discharge tube having a reentrant stem, a tubularelectrode having one end directed toward said stem, an electrode surfacepresented to the interior of said tubular electrode, a conductorextending through said stem for conducting current to said surface, anannular metallic surface presented to the space between said tubularelectrode and said electrode surface intermediate said stem and saidelectrode surface, said annular surface having a radial dimension atleast approximately as great as the difference in diameters between saidtubular electrode and sa .d electrode surface, and a surface extendinglengthwise of the tube from. the outer edge of said annular surface inclose juxtaposition to the inner surface of the tube.

11. An electrical discharge device having a reentrant stem, an electrodeopposite said stem, a smaller electrode surface between said stem andelectrode, a shielding surface intermediate said stem and electrodesurface, said shielding surface extending outwardly from a diametersubstantially confined to that of said electrode surface to a diameterat least substantially as great as that of said electrode, and anothershielding surface extending longitudinally of the tube from the outeredge of said shielding surface, the longitudinal surface beingsurrounded by a thin CHARLES G. SMITH.

